A hull of a watercraft may encounter a variety of problems when it remains submerged in a lake, bay or other body of water for a protracted period of time. For example, exterior surfaces of the hull that are submerged in the water may acquire a significant amount of marine growth that may impair the performance of the watercraft and superficially damage the hull if not frequently removed. Further, the hull may be subjected to significant physical damage in cases where the hull is exposed to strong wave activity resulting from weather conditions or the wakes of passing watercraft. This damage generally occurs where the hull of the watercraft repeatedly contacts a stationary object such as a portion of a dock or buoy, or even another watercraft that is docked or moored nearby.
Although the foregoing difficulties may largely be avoided by removing the watercraft from the water and transporting the watercraft to a storage location when the watercraft is not in use, this approach is seldom employed, since a significant effort is generally required to remove and transport the watercraft, and is particularly inconvenient in situations where the watercraft is subject to frequent use.
One approach that addresses the foregoing difficulties is a watercraft lift. An example of one type watercraft lift is described in U.S. Pat. No. 5,908,264 to Hey, which is incorporated by reference herein. The watercraft lift generally includes a user-actuated mechanical lifting mechanism that is positioned below the watercraft and moved upward to engage the hull of the watercraft and lift the watercraft from the water and to support watercraft above the surface of the water when not in use. When it is desired to refloat the watercraft, the user is able to lower the lifting mechanism to lower the watercraft into the water. The watercraft lift is therefore a particularly convenient solution to the foregoing difficulties, since the watercraft may be quickly removed from the water during periods of non-use, and refloated when desired, with minimal human effort.
This invention generally relates to an apparatus for supporting a hull of a watercraft, and more particularly, to a hull support apparatus that may be used with a watercraft lift.
The present invention is directed to an apparatus for supporting the hull of a watercraft. In one aspect of he invention, a bunk beam and bunk cushion assembly is provided, which includes an elongated bunk beam having an elongated cushion support surface portion oriented at a predetermined fixed angle to the horizon so as to be facing toward the hull of the watercraft when in use to support the watercraft, and an elongated bunk cushion having a lower surface portion in supporting engagement with the cushion support surface portion of the bunk beam and an upper watercraft support surface portion engageable with the watercraft hull. The cushion upper surface portion is convex in shape and projects away from the cushion lower surface portion. The cushion support surface portion of the bunk beam holds the cushion upper surface portion facing toward the hull of the watercraft for engagement therewith when in use to support the watercraft. The bunk cushion and the bunk beam being attached together in stationary relation for movement as a unit.
In another aspect of the invention, the assembly includes an elongated bunk beam having an elongated cushion support surface portion and a longitudinally extending slot, and an elongated bunk cushion having a lower surface in supporting engagement with the cushion support surface portion of the bunk beam and an upper watercraft support surface engageable with the watercraft hull. The bunk cushion has a longitudinally extending locking rib projecting away from the cushion lower surface and into the slot. The cushion locking rib has a thickness sufficient to provide shear strength to maintain the bunk cushion in position on the cushion support surface portion of the bunk beam against side loading forces exerted by the watercraft during use.
The bunk beam has sufficient stiffness to support a portion of the weight of the watercraft transmitted through the bunk beam without permanent deformation but is yieldable to at least partially conform to the shape of the watercraft hull under the portion of the weight of the watercraft supported thereby.
The assembly may be used for attachment to first and second booms rotatable in a substantially vertical plane. The bunk beam includes at least one attachment member configured to be pivotally attached to the first and second booms to move the bunk beam and bunk cushion as a unit in the substantially vertical plane with the first and second booms, with the bunk beam and bunk cushion comprising a non-movable assembly when in an elevated position supporting the hull of the watercraft.
The slot in the bunk beam may be a portion of a longitudinally extending recess therein having a neck portion toward the cushion support surface and an anchor portion positioned away from the cushion support surface. The recess anchor portion has a width greater than the recess neck portion. The locking rib may have a neck portion toward the cushion lower surface and a lock portion positioned away from the cushion lower surface, with the cushion neck portion having a width sized to fit within the recess neck portion and the cushion lock portion having a width sized to lockably fit within the recess anchor portion. The cushion lock portion width is greater than the recess neck portion and has a thickness sufficient to not pull through the recess neck portion to maintain the bunk cushion in position on the cushion support surface portion of the bunk beam against lifting forces exerted by the watercraft during use.
In the disclosed embodiment, the bunk beam has a set of first locking elements and the bunk cushion has a set of second locking elements coupled together to form a bunk beam and bunk cushion assembly. The bunk beam has a cushion support surface portion configured to support a cushion lower surface and the plurality of first locking elements include a longitudinally extending central recess in the bunk beam projecting away from the cushion support surface.
In the disclosed embodiment, the plurality of first locking elements further include a pair of oppositely projecting flange portions, and the plurality of second locking elements further include a pair of oppositely projecting side extensions. Each of the side extensions extend around and grasp a correspondingly positioned one of the pair of flange portions.
The assembly is usable for attachment to a pair of support booms. The bunk beam can include first and second support webs or sidewalls rigidly attached to an attachment surface having the cushion support surface to which the bunk cushion is attached. The first and second support webs project away from the attachment surface on a side thereof away from the cushion support surface and are configure to attach to the support booms. The first and second webs have toward each end portion of the bunk beam a transverse bore sized to receive a pin for pivotal connection of the bunk beam to a correspondingly positioned one of the pair of support booms. The first and second webs having a lower wall portion and an upper wall portion positioned between the lower wall portion and the cushion support surface portion. The lower wall portion has a wall thickness greater than the wall thickness of the upper wall portion in at least the area around the transverse bores to provide within the transverse bores a bearing surface for engagement with the pin when extending therethrough.